Method of producing highly polished metal reflectors



Nov. 10, 1931. v. 1.. OESTNAES ET AL 1,831,541

METHOD OF PRODUCING HIGHLY POLISHED METAL REFLECTORS 2 Sheets-Sheet l gnuwntoza Filed June 2, 1928 attozweq NOV. 10, 1931. v QESTNAES ET AL 1,831,541

METHOD OF PRODUCING HIGHLY PO LIS-HED METAL REFLECTORS Filed J1 1ne 2, 1928 2 Sheets-Sheet. 2

Patented Nov. 10, 1931 UNITED STATES PATENT OFFICE VICTOR L. OESTNAES, F WESTFIELD, AND RICHARD W.

JERSEY, ASSIGNORS TO AMERICAN GASACCUMULATOR COMPANY, OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY METHOD OF PRODUCING HIGHLY POLISHED METAL REFLECTORS Application filed June 2, 1928. Serial No. 282,464.

Our invention relates to methods which may be employed to produce highly polished reflecting surfaces upon metal.

The method is of special utility in the providing of highly polished surfaces upon metal, such as metal sheets whichvhave been pressed or otherwise formed into configurations such that it is diflicult, if not practically impossible, to effect polishing of the surfaces thereof by the employment of the usual polishing means and methods.

The general objectof our invention is to provide a novel method by the employment of which highly polished surfaces may be provided or formed upon metal.

It also is an object of the invention to provide a method of novel character whereby a polished light-reflecting surface may be formed or produced upon a body of metal, such as a metal sheet, by the application of pressure thereto preferably accompanied by a simultaneous rubbing action.

A further object of the invention is to provide a novel method whereby a metal which is of. such character that it is not suitable for use in the production of light reflectors may be provided with a surface or surfaces which is or are light-reflecting.-

lVe shall not at this point set forth other objects oft-he invention but in the course of the detailed description thereof, which follows additional objects will be specifically referred to or else will become apparent from such description.-

In order thatthe invention may be understood more readily and its practical advan tages rendered more fully apparent refen ence should be drawings to which reference will be made in the following description. \Vhile in the- .drawings We have indicated reflectors of certain kinds in the manufacture of whichthe method of our invention may be employed it is to be understood that the invention may be employed in the manufacture of reflectors of other shapes and of other characters than those "which are illustrated.

In the drawings: v

Fig. 1 is a View in front elevation of a partially formed or completed central triple rchad to the accompanying" flector unit in the completion of which our invention is adapted to be employed;

Fig. 2 is atransverse sectional view thereof taken on the line 2-'-2 of Fig. 1;

Fig. 3. is a view similar to that shown in Fig. 2 butindicating that an additional step in accordance with our invention has taken place;

Fig. 4 is a view indicatin the manufacture of a centraT triple reflector unit in accordance with our invention;

Fig. 5 is a view in front elevation of the ipmpleted reflector unit shown in section in Fig. 6 is. a view in section of a reflector of a different construction, the said section being-taken ina plane including the prin-. cipal axis of the; reflecting surface;

Fig. 7 is a view in front elevation of a fragmentary portion of a reflector showing a plurality of self-focusing or central triple a final step in reflectors located in contiguous relation to each other and integrally connected;

Fig. 8 is a view in transverse section of a fragmentary portion of a reflector such as isshown in Fig. 7; and

Figs. 9. and 10 are sectional views of a fragmentary portion of a plate having a portion thereof subjected to-treatment in ac cordance with the'method of our invention, the said views being indicative of the broad principle ofapplication of our invention.

' The principle of our invention is such that the desired results ma be obtained in different ways but in t e description which follows we shall describe only the way or method which is at present preferred by us.

For purposes of description we shall assume that it is desired to provide upon a relatively soft metal as a base or support, which may be and usually is-a' relatively cheap '-metal'(e. g. copper) a polished surface of a character to reflect light; and we shall further assume that it is desired to provide such light-reflecting surface of silver upon a copper plate pressed or otherwise formed into a shape desired.

' One of the ways in which the method of our invention may be carried out may be described by reference to Figs..1 to 5. of the LUCIE, 0F MAPLEWOOD, NEW

drawings. In these figures of the drawings we have indicated the steps to be carried out when our invention is employed in the manufacture of a self-focusing or central triple reflector of-hollow type. In Figs. 1 and 2 a hollow structure of the type indicated is shown, the same having been formed by means of pressure between male and female die'members (not shown) from a plate of suitable metal, for example, copper. The formed member shown in Figs. 1 and 2 comprises sides 1, 2 and 3 which are arranged in planes at right angles to each other. A sheet of suitable metalhaving been pressed into the desired shape as shown in Figs. 1 and 2 or into some other desired shape, it is subjected to an annealing operation and thereafter it is provided in any known manner, as by electro-chemical or electrolytic action, with a coating or plating of silver or .other suitablemetal 5, as shown in Fig. 3, the surface of which may be highly polished by pressure and thereby rendered light-reflecting.

After the pressing operation above referred to the inner surfaces of the sides 1, 2 and 3 are not optically smooth and plane but on the contrary there are slight roughnesses or'projections present. These roughnesses or projections will be apparent upon the inner surfaces of the plating or coating 5. The plating or coating 5 having been formed upon the inner side or surface of the structure shown in Figs. 1 and 2, the latter is then placed within a cavity 6 provided in a mold member 7. This having been done a plunger or die member 8 is caused to enter the cavity of said structure and to contact with theinner surface of the coating 5 "upon the sides 1, 2 and 3. It

face of the die 8 are given the same polish as that uponthe face of said die. We have found that a die or plunger consisting of hardened steel, the formin face of which consists of a plating 12 o a suitable hard non-oxidizing metal, such as chromium, may be employedwith satisfactory and good results. at is desirable that a die or plunger havin a formin face of non-oxidizing metal be employe otherwise in use and in time the high polish of itsforming face will disappear and it will not be feasible in practice to continue. its use without repolishing the forming face thereof.

teams].

As has been indicated already, the .sur-

faces of the sides of the die or plunger 8 are highly polished. When the die or plunger 8 enters the cavity formed by the sides 1, 2 and 3 the forming sides thereof contact first with the minute projections or irregularities in or upon the surface of the metal coating 5. The projections as well as the rounded character of the plate along the line between adjoining sides and also at the point of convergence of the said sides, as shown in Figs. 1 and 2, tend to prevent the entry of the said die into the cavity 6 to the full extent possible. The great pressure, however, applied to the die causes the flattening and smoothing out of the surfaces of the sides of the metal coating or platin 5. It will be apparent, therefore, that in the final pressing operation there is slight relative lateral movement between the forming face of the die or plunger 8 and the contacting surfaces of the metal coating 5 upon the sides 1, 2 and 3. In other words, there is a slight rubbing action of the sides, of the die upon the corresponding contacting sides of the metal coating 5. In consequence the surface of the coating is caused to assume a-high polish corresponding to the polish of the sides of the die or plunger 8.

We have found that when a die or plunger of hard metal, having preferably a face or faces of non-oxidizable metal having a high degree of polish, is employed a corresponding polish may be imparted by pressure to a metal acted upon by thesaid die or plunger whereby light reflectors having highly polished light-reflecting surfaces may be produced at relatively low cost.

While it is practicable, as indicated in Figs. 9 and 10, to produce a highly polished surface by pressure according to the principle as hereinbefore described when pressure is ap lied. by means of a die in a direction at rig t angles to the planes of the contacting surfaces, yet it isdesirable' wherever practical that the pressure be applied in directions forming acute angles with the contacting cooperating surfaces so that relative lateral movement between the contactingsurfaces of the face of thedie or plunger and'of'the body being acted upon by the die may be more tary portion of'a flatplate,"one portion 20 of In Figs. 9 and'lQ'w have shown a fragmenwhich, shown in Fig. 9, has been subjected to pressure. In Fig. 10 the pressed portion 20 is shown as having been provided with a metal coating or plating 21, the latter having beenapplied after the subjection of the plate shown in Fig. 9 to an annealing o eratien. After having applied the metalp atin'g" or coating 21 the latter is. then subjecte'tl ito heavy pressure by means of a die, "thep'ortibri f of which which is adapted to contact with the surface of metal coating being preferably non-oxidizable and very hard. A suitable die to form a polished surface upon the metal plating orcoating 21. When, as in Figs. 9 and 10, the force of the die or plunger is applied in a direction at right angles or substantially so to the surface being acted upon it is desirable for the best results that the applied force be suflicient to cause lateral flow of the metal of the plate or metal body being acted upon.

In Fig. 6 we have shown a parabolic mirror manufactured in accordance with the method andprinciple of our invention. In the manufacture of the mirror 25 shown in Fig. 6 we employ a sheet of suitable metal, for example, copper, and press it into a shape providing approximately an inner parabolic surface. It is then subjected to an annealing operation, as previously described with respect to the reflector shown in Figs. 1 to 5 inclusive, after which a layer or coating of suitable metal 26 such as silver is deposited upon the inner side thereof. The deposition of such metal coating or plating may be effected electrolytically or it may be effected as a result of chemical reactions as may also the coating shown in previous figures of the drawings. The .metal plating or coating having been provided upon the inner surface of the previously formed metal sheet, it is then subjected to heavy pressure between the co-act-.

ing male and'female members of a mold in known manner. The forming face of the die or plunger member should consist of a hard preferably non-oxidizable' metal, such aschromium, which has been highly polished so that it is light-reflecting. Upon the a plication of such a surface to the inner sur ace of the metal coating or plating 26 the inner surface of the latter'is given a like high pollsh so that it becomes light-reflecting.

In Figs. 7 and 8 we have shown a construction of reflector 30 in'which a plurality of reflector units 31 are located in contiguous relation'to each other,- Preferably these reflec tor units 31 are integral with each' other and are formed from a plate of suitable metal pressed between the properly shaped members of a mold. The method employed is identical with that heretofore described in that a sheet of metal 32 is first pressed -so as" to form units of approximately the shape desired, after which one or both sides is or are coated, one side only being shown in the drawings as provided with a coating or plating 33 of a suitable metal, such as silver, as shown in Fig. 8. It will be understood, however, that the opposite side may be coated if desired so that both sides of the structure as shown in Figs. 7 and 8 in the completed structure might be light-reflect ing. After the initial pressure of the plate 32 into approximate shape as before stated it is annealed, after which the coating or coatings of suitable metal such as silver is or are applied in the manner heretofore indicated or in any other known manner.

Thereafter the several reflector units are subforming faces of both members of the mold employed should consist of hard metal, which preferably should be non-oxidizable.

In every case where it is expected that a highly polished light reflecting surface is to be formed by pressure as described the forming face of the die or mold member must be highly polished because our process or method presupposes that the pressure which shall be employed shall be suflicient to cause the surfaces acted upon to constitute an exact replica or duplication of theforming surface of the mold or die member in contact therewith. V

As already indicated,.it is preferable in the employment of the method of our invention in the production of light reflectors of the character indicated'and suggested that there should be relative lateral movement between the surface of the forming face of the dieand the surface of the reflector to be rendered light-reflecting.

By our invention we have provided a method by which light reflectors may be constructed from sheets of suitable metal of a character to be readily worked and pressed into desired shapes, such shapes being in acand then subjecting it to pressure by means of ,a die, the contacting portion .of which is very hard and the contacting surface of which is provided with a polish of the character which it is desired to impart to the surface of the said bodywhich it is desired to render light-reflecting.

2. The method of providing a metal body with a highly polished light-reflecting surface which comprises the shaping of the said body to produce a surface of the configuration desired, annealing the said body, de-

positing upon the said surface a platiu of metal which is adapted when polishe to reflect light and subjecting the portion of the surface of the said plating which it is desired to render light-reflecting to high ressure by means of a die, the forming surace of which has the degree of high polish which it is desired to im of the said metal body W ichit is desired to render light-reflecting.

3. The method of producing a'highly polished surface upon ametal late which comprises the stamping thereo' to form it into approximately. the configuration desired, annealing the, same, depositing a coating of metal upon the s'urfacegthereof which it is desired to render light-reflecting and then subjecting the same to pressure by means of a die, the surface of theforming portion of V which is of the same shape as that of the K surface-which it is desired to produce and render light-reflecting, the contacting surface of the said die having the degree of polish which it is desired to impart to the surface of the said plate.

4. The method of roducing a hollow refle'ctor, which comprises the stamping of a metal plate to form thesame to a shape having a cavity upon a side thereof, annealing the said plate, depositing upon the inner sides of said cavity a coating of metal which is adapted to receive a polish to render it light-reflecting and thereafter subjecting the same to pressure by means of a die of a shape to fit the said cavity, the surface of. the said die having the degree of polish which it is desiredtoimpart to the inside surfaces of the said metal coating.-

5. The method of producing a concave metallic ,reflecton. which-.zcomprises deposib ing upon the concave surface of a metal blank a coatingof the metal which is to constitute the reflecting surface and thereafter pressing against the coated concave surface a highly polished final shaping die of different form or contour from that of the said concave s urfaceto set the metal of the blank in the desired shape and to renderthe reflecting surface bright.

6. The method of producing a concave metallic reflector which comprises the pressing of a sheet metal plate to form a concave surface upon one side thereof, depositing upon the concave surface thereof a coatingof a metal which is to constitute the reflecting surface and thereafter pressing against "the coated concave surface a highly polished final shaping die of different form or con-' tour from that of the said concave surface to set the metal of the blank in the desired shape and to render the reflecting surface bright.

7. The method of producing a metallic reflector which comprises depositing upon the hollow surface of a metal blank a coating of rt to the surface andto render the reflecting surface bright.

8; The method of producinga concave metallic reflector which comprises depositingv uponthe concaved surface of a metal blank a coating. of the metal which is to constitute the reflecting surface, and thereafter pressing against the coated concave surface a highly polished final shaping die to set the metal of the blank in the desired shape and toxrender the reflecting surface bright. 7

'9. The method of producing-a metallic reflector which comprises depositing upon the surface of ametal blank a coating of the metal which is to constitute the reflecting surface and. thereafter pressing against the coated surface a highly polished sha ing die to set the metal of the blank in the s ape desired and to render the reflecting surface light reflecting. v 10. The method of producing a concave metallic reflector which comprises the pressing of a highly polished shaping die against a metal blank to form and set the metal of the blank about said die, and subjecting the metal of the blank simultaneously to high pressure by 'saiddie to impart to the surface of the blank which is in contact with the die and polish of the said die to thereby render the said surface light reflecting.

11. The method of producing a concave metallic reflector which-comprises. the pressing of a sheet metal platetoform a concave as our invention, we have hereunto signedour names this 29th dav of May, A. D. 1928.

' vic'rou L. oEsrNAhs.

-RICHARD- W. LUCE. 

